This invention relates to a method of manufacturing liquid crystal display devices and in particular to a method of manufacturing a color-matrix-type liquid crystal display device having self-aligned color filters formed on an active matrix substrate.
The commonly known technique for coloring a matrix liquid crystal display device is to use color filters. This may be done, for example, by arranging color filters with coloring regions in the form of a regularly repeating sequence of stripes or dots that are separately applied and are of the three additive primary colors (red, green and blue). Generally, a matrix-type liquid crystal display (LCD) device comprises a matrix substrate having a plurality of display electrodes, a counter substrate spaced from the matrix substrate, and liquid crystal filling the space between the two substrates. Color filters, in a conventional matrix-type LCD, are arranged in the counter substrate, i.e., they are manufactured independently from the matrix substrate before assembly of the display device. An electrodeposition method for manufacturing stripe-type color filters is described in M. Suginoya et al. "Multicolor Graphic LCD with Tri-Colored Layers Formed by Electrodeposition," Japan Display '83 pages 206-209, Oct. 4, 1983. Since there is necessarily a space between the display electrodes (on the matrix substrate) and the color filters (on the counter substrate), the space being necessary for filling with liquid crystal, such an LCD produces color misalignment due to parallax. It is also very difficult, during assembly of such a device, to precisely align each display electrode and the corresponding color filter.
In order to overcome these drawbacks, it has been proposed to form dot-type color filters directly on each display electrode on the matrix substrate, using a printing technique (see, for example, Japanese Patent Application No. 56-140324 (kokai)). However, a printing technique involving sublimation transfer by heating or evaporation causes color misalignment or undesirably mixed colors, especially when it is used for production of LCD's having a large area or a large number of tiny picture elements.